Acetylenic nickel compounds



United States Patent 3,088,962 ACETYLENIC NICKEL COMPOUNDS MichaelDubeck, Royal Oak, Mich, assignor to Ethyl Corporation, New York, N.Y.,a corporation of Virginia N0 Drawing. Filed Sept. 12, 1960, Ser. No.55,180 10 Claims. (Cl. 260439) This invention relates to novelorganometallic com pounds and their mode of preparation Morespecifically, this invention relates to bis(cyclomatic nickel)acetylenic compounds as hereinafter described.

An object of this invention is to provide a novel class ofbis(cyclomatic nickel) acetylene compounds. A further object is toprovide a process for the preparation of these compounds. Additionalobjects will become apparent by a reading of the specification andclaims which follow.

The objects of this invention are accomplished by providing compoundsrepresented by the formula:

ZCECZ" CyNiNiCy' Although not bound by any theory, these compounds arebelieved to have the structural formula as follows:

In the above formula, at least one of the groups Z and Z, as describedlater, is an electron withdrawing group. The other Z substituent groupcan either be an electron withdrawing group or can be a monovalentsubstituent group which is unreactive with nickel and which is not anelectron withdrawing group. Cy and Cy represent cyclomatic hydrocarbongroups which donate five electrons to the nickel atoms for bonding. Byvirtue of the electrons donated to each of the nickel atoms from thecyclomatic hydrocarbon groups, the acetylenic molecule, and the othernickel atom, each of the nickel atoms present in the molecule achievesthe inert gas configuration of krypton.

The cyclomatic hydrocarbon groups, designated by the symbols Cy and Cyin the above formula, may be the same or different and arecyclopentadienyl-type hydrocarbon radicals. By this, it is meant thatthe radical con tains the cyclopentadienyl moiety. In general, suchcyclomatic hydrocarbon groups can be represented by the formulae:

s Eli; R1 WERE] RP R R wherein the Rs are selected from the groupconsisting or hydrogen and univalent hydrocarbon radicals.

A preferred class of cyclomatic radicals suitable in the practice of myinvention are those which contain from five to about 13 carbon atoms.These are exemplified by cyclopentadienyl, indenyl,methylcyclopentadienyl, propylcyclopentadienyl, diethylcyclopentadienyl,phenylcyclopentadienyl, tert-butyl cyclopentadienyl, p-ethylpheny)cyciopentadienyl, 4-tert-butyl indenyl and the like. The compounds whichyield these radicals are preferred as they are the more readilyavailable cyclomatic compounds, and the compounds of my inventioncontaining these radicals have the more desirable physicalcharacteristics which render them of superior utility.

As shown in the above formula, the bridging acetylenetype molecule isbelieved to be bonded to both of the nickel atoms in forming thecompounds of my invention. As visualized, the triple bond in thebridging acetylenic 3,088,962 Patented May 7, 1963 compound is reducedto a single bond thus making four electrons available for bonding to thetwo nickel atoms. Each of the carbon atoms on either side of the triplebond is thereby bonded to each of the nickel atoms. The actualconfiguration of the bridging acetylenic molecule is believed to beapproximately at right angles to the plane in which the twointer-connected nickel atoms lie. This is shown in the above formula bymeans of the dotted lines indicating bonding of the carbon atom which isbehind the plane of the paper to the two nickel atoms illustrated aslying in the plane of the paper. The other carbon atom which is bondedto the two nickel atoms is depicted as lying in front of the plane ofthe paper. Thus, the bonds between this carbon atom and the two nickelatoms are drawn at solid lines.

At least one of the substituent groups, Z or Z as shown in the aboveformula, is an electron withdrawing group. The other substituent groupcan also be an electron withdrawing group or can be a monovalentsubstituent group which is unreactive with nickel and further is not anelectron withdrawing group. Typical of the electron withdrawing groups Zand/or Z are the following:

secn

In the above electron withdrawing groups, which are typical of Z and Z,R can be any group which does not react with the nickel reactant.Typically, R is a monovalent hydrocarbon group which may be an alkyl,aryl, aralkyl, alkaryl, alkenyl, cycloalkyl, cycloalkenyl and the like.Typical of such groups are methyl, tert-butyl, cyclohexyl, propenyl,benzyl, p-methylphenyl and the like. Preferably, R does not contain morethan 10 carbon atoms. X denotes a halogen group such as fluoro, chloro,bromo or iodo. When X is attached to a carbon atom which is in the alphaposition relative to the triple bond of the bridging acetyleniccompound, X is preferably fluorine. Since the fluorine atom is smallerthan the other halogen atoms, it does not tend to sterically interferewith the reactivity of the acetylenic triple bond to the extent thatlarger halogen atoms do.

As indicated previously, when one of the Z substituent groups is anelectron withdrawing group, the other Z substituent may be monovalentgroups such as hydrogen, a monovalent organic group such as alkyl, aryl,aralkyl, alkaryl, alkenyl, cycloalkyl, cycloalkenyl and the like whichdoes not react with the nickel reactant and is not an electronwithdrawing group. The groups may also contain non-hydrocarbon atomssuch as in the case of a mercuro halide, a silyl, phosphine, arsine orstibinc group. Typical of such substituent groups which are not electronwithdrawing groups are the lower alkyls, e.g. methyl,

ethyl, butyl, amyl and octyl; the aryls such as phenyl, anthracyl andthe like; aralkyl groups such as benzyl, phenylbutyl, phenylheptyl andthe like; alkaryl groups such as p-ethylphenyl, amylphenyl andheptylphenyl; alkenyl groups such as 3-buten-l-yl, 1-tridecen-13-yl,2,4-butadien-1-yl and the like; cycloalkyl groups such as cycllohexyl,4-methylcyclopentyl and cyclooctyl, and cycloalkenyl groups such ascyclopentadienyl, cyclohexenyl and the like. Preferably, the monovalentgroup is a hydrocarbon group and contains no more than 13 carbon atoms.

The novel compounds of my invention are formed according to thefollowing reaction scheme:

ZCE CZ QCECQ' CyNiNiCy- As shown, my process involves a displacementreaction wherein one acetylenic molecule, ZCECZ, displaces anotheracetylenic molecule, QCECQ, from a bis(cyclo matic nickel) acetylenicreactant, QCECQ'CyNiNiCy'. As a result, there is formed a newbis(cyclomatic nickel) acetylenic compound having the formula ZCE CZCyNiNiCy The above reaction is reversible. Thus, my process, in itsbroadest form, embodies the concept of displacing any acetylenic groupwith another acetylenic group from a compound QCEC-Q-CyNiNiCy wherein Qand Q are defined below and, in which the acetyleuic group bridges andis bonded to both nickel atoms in the manner described previously. Thepreferred embodiment of my process involves using as the displacingacetylenic group a compound ZCECZ as described above. This embodiment ispreferred because, as will be described later, the acetylenic groupZCECZ reacts with nickelocene to form compounds having the formulaZCzCZ-CyNiNiCy. Thus, my preferred process aifords a way to makecompounds ZCECZCyNiNiCy which cannot be made, except in low yield, bydirect reaction of an acetylenic compound, ZCECZ', and a bis(cyclomatic)nickel com pound CyNiCy'.

The compounds formed by my process,

and the displacing acetylenic reactant, ZCECZ', are both describedabove. The bis(cyclomatic nickel) acetylenic reactant, QCECQ-CyNiNiCy,is defined in detail in my prior co-pending application Serial No.852,216, filed November 12, 1959. As set forth in that application,

In this formula, Q and Q represent either hydrogen or univalenthydrocarbon radicals containing from one to about 10 carbon atoms. Cyand Cy represent cyclomatic hydrocarbon groups which donate fiveelectrons to the nickel atoms for bonding. By virtue of the electronsdonated to each of the nickel atoms from the cyclomatic hydrocarbongroups, the acetylene molecule and the other nickel atom, each of thenickel atoms present in the compounds achieves the inert gas electronconfiguration of krypton.

As can be seen by comparing the structural formula of my novelorganometallic compounds,

ZCE CZ CyNiNiCy with the structural formula of the organ-onickelreactant, QCECQ-CyNiNiCy, they are identical except for the differencein the acetylenic group which is bonded to and bridges the two nickelatoms in the molecule. The compounds, QCECQ-CyNiNiCy, as described in myprior application Serial No. 852,216, are formed by direct reaction ofan acetylenic compound and a bis(cyclomatic) nickel compound.Surprisingly, the compounds of the present invention, ZCECZ-CyNiNiCy,are formed, if at all, in low yield by reaction of a bis(cyclomatic)nickel compound and an acetylenic compound, ZCECZ, in which at least oneof the Z groups is an electron with drawing group. This is illustratedby reference to my prior co-pending application Serial No. 30,075, filedMay 19, 1960, now abandoned, where there is described the reaction of abis(cyclomatic) nickel compound with an acetylenic compound, ZCECZ, togive primarily a compound having the formula, CyNiCy-ZCECZ.

By virtue of the present invention, it is now possible to form binuclearcyclomatic nickel compounds,

in which Z or Z is an electron withdrawing group. The electronwithdrawing substituent groups, Z or Z or both, on the bridgingacetylenic molecule are reactive groups and thereby permit the use ofthe binuclear cyclomatic nickel-acetylenic compounds in a host of newapplications. Because of the reactive nature of the substituent groups,Z and Z, my compounds can be utilized as intermediates in thepreparation of nickel-containing polymers. Also, my compounds find greatutility as intermediates in the preparation of new organic compounds.

My process is normally carried out in the presence of a solvent althoughin certain cases the acetylenic reactant, ZCECZ, may, if used insufficient excess, serve as the solvent. In general, any unreactivesolvent may be employed in which the bis(cyclomatic nickeD-acetylenicreactant is sufficiently soluble. Typical of such solvents are highboiling saturated hydrocarbons such as n-octane, n-decane, and otherparatfinic hydrocarbons having up to about 20 carbon atoms such aseicosane, pentadecane and the like. Also applicable are aromaticsolvents such as benzene, toluene, mesitylene, and the like. Typicalether solvents are ethyl octyl ether, ethyl hexyl ether, diethyleneglycol methyl ether, diethylene glycol diethyl ether, diethylene glycoldibutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethylether, trioxane, tetrahydrofuran, ethylene glycol dibutyl ether and thelike. Ester solvents which may be employed include pentyl butanoate,ethyl decanoate, ethyl hexanoate, and the like. Silicone oils such asthe dimethyl polysiloxanes, bis(chlorophenyl) polysiloxanes,hexapropyldisilane, and diethyldipropyldiphenyldisilane may also beemployed. Other ester solvents are those derived from succinic,glutaric, adipic, pimelic, suberic, azelaic, sebacic and pinic acids.Specific examples of such esters are (ii-(- ethylhexyl) adipate,di-(Z-ethylhexyl) azelate, di-(Z-ethylhexyl) sebacate,di-(methylcyclohexyl) adipate and the like. Preferred solvents are thepolar ethers such as diethylene glycol dimethyl ether andtetrahydrofuran.

A further criteria for the solvent is that it be one which is easilyseparable from the compounds formed in the process. If, for example, theproduct is a liquid, the solvent should be selected so that it has anormal boiling point differing by at least 20 C. from the normal boilingpoint of the liquid product. Use of such a solvent enables separation ofthe product by means of distillation. If the product is a solid, thesolvent should be selected so that its freezing point is sufficientlylow to enable separation of the product therefrom by means ofcrystallization.

Although not critical, it is generally desirable to agitate the reactionmixture when carrying out my process. Agitation, especially if thereactants are not mutually soluble in the reaction solvent, insures ahomogeneous reaction mass and an even reaction rate. Obviously, bothconditions are desirable since they increase the efficiency of theprocess.

I generally employ a large excess of the acetylenic reactant, ZCECZ, inmy process. The displacement reaction through which my process functionsis reversible, and use of excess acetylenic reactant tends to force thereaction to completion. Further, the acetylenic reactant, ZCECZ', isgenerally cheaper than the nickel reactant, QCzCQ' CyNiNiCy. Thus, thepresence of excess 'acet'ylenic reactant, ZCECZ, tends to force thereaction to completion so as to consume all of the nickel reactant,QCECQ-CyNiNiCy'. In some instances, such as when the displacedacetylenic moiety, QCECQ', is gaseous so that it can be readily removedfrom the reaction system, it is not necessary to employ an excess of theacetylenic reactant, ZCECZ'.

My process is generally carried out at a temperature from about zero toabout 110 C. Preferably, however, my process is carried out from about60 to about 80 C. since within this temperature range yields aremaximized while undesirable side reactions are minimized. The pressureemployed in my process is not critical and generally, the process can beconducted at atmospheric pressure. If desired, however, my process canbe conducted under pressures up to about 100 atmospheres.

My process is preferably conducted in the presence of a blanketingatmosphere of an inert gas. Typical of such gases are krypton, neon,argon and the like. A preferred inert gas is nitrogen since it isrelatively cheap and readily available. The function of the inert gas isto protect the reactants and products of my process against oxidation.

The product, ZCECZ-CyNiNiCy, formed in my proc ess can be separated fromthe reaction product by conventional means. Typical means of separationare chromatography and fractional crystallization.

To further illustrate my novel compounds and the novel process by whichthey are prepared, there are presented the following examples in whichall parts and percentages are by weight unless otherwise indicated.

Example I A mixture comprising two parts of bis(cyclopentadienyl nickel)acetylene and 1.5 parts of dimethyl acetylene dicarboxylate dissolved in35.5 parts of tetrahydrofuran was charged to a reaction vessel that wasequipped with a condenser which was connected through a protectivedrierite tube to a water-leveled gas measuring tube. After purging thereaction system thoroughly with nitrogen, the reaction mixture washeated at reflux for 18 hours. At the end of this time, the quantity ofgas which had been evolved was 50 percent of that predicted by theoryfor displacement of all of the acetylene from the bis(cyclopentadienylnickel) acetylene reactant. By this time, the reaction mixture hadchanged in color from a dark green to a dark brown. The reaction productwas discharged and was reduced to one-half its volume by heating invacuo. It was then diluted with an equal volume of petroleum ether, anda green-brown solid precipitate was formed. The mother liquor wasdecanted from the precipitate and cooled to 0 C. where a new precipitateformed. The mother liquor was again decanted and cooled to 40 C. atwhich point a third precipitate formed. The mother liquor was againdecanted and cooled again to -40 C. to give a fourth precipitate. Atthis point, the remaining mother liquor was decanted and heated underreduced pressure to remove solvent and give a fifth isolated solidfraction. The first solid fraction was chromatographed on an aluminacolumn using a :70 (volume ratio) mixture of benzene and petroleum etheras the solvent and eluant. The remaining fractions were chromatographedon similar columns employing pure benzene as both the solvent andeluant. By this procedure, there were isolated two fractions whichdiffered considerably in polarity. The less polar material wasbis(cyclopentadienyl nickel) acetylene, of which 1.0 part was recovered.The more polar green fraction, which exhibited strong absorption onalumina, was purified by recrystallization from low-boiling petroleumether followed by sublimation at 60 C. and 0.05 mm. Hg. There wasobtained 0.57 part of bis(cyclopentadienyl nickel) dimethyl acetylenedicarboxylate in the form of dark green crystals having a melting pointof 103 C. On analysis, there was found: C, 49.6; H, 4.12 percent with amolecular weight, according to the Signer Method, of 384. Calculated forC H O Ni C, 49.3; H, 4.11 percent with a molecular weight of 390.

Example II A solution comprising one mole of bis(cyc1opentadienylnickel) acetylene and 1.5 moles of diethylacetylcne dicarboxylate intoluene is charged to a reaction vessel under nitrogen. After heatingfor eight hours at 110 C. and atmospheric pressure, the reaction productis discharged. Excess solvent is stripped from the reaction product, andthe residue is chromatographed on alumina using a 30:70 (volume ratio)benzene-petroleum ether mixture. A good yield of bis(cyclopentadienylnickel) diethylacetylcne dicarboxylate is obtained from the eluate bymeans of fractional crystallization.

Example 111 A solution comprising 0.5 mole of bis(cyclopentadienylnickel) propyne-l and 1.0 mole of diisopropylacetylene dicarboxylate inbenzene is charged to a reaction vessel under nitrogen and heated for 15hours at 30 C. at atmospheric pressure. The reaction product is thendischarged, and a good yield of bis(cyclopentadienyl nickel)diisopropylacetylene dicarboxylate is obtained from the reaction productby means of chromatography followed by fractional crystallization of thecluate.

Example IV A solution comprising one mole of bis(cyclopentadienylnickel) butyne-Z and one mole of dicyano acetylene in tetrahydrofuran ischarged to a reaction vessel under nitrogen and heated for 10 days at 20C. and atmospheric pressure. The reaction product is then discharged;solvent is removed by heating in vacuo, and the residue is dissolved inpetroleum ether and chromatographed on alumina. A good yield ofbis(cyclopentadienyl nickel) dicyano acetylene is recovered from theeluant by means of fractional crystallization.

Example V A solution comprising 0.1 mole of bis(cyclopentadienyl nickel)acetylene and 0.3 mole of dimethyl-4,4'-acetylenedibenzoate indiethylene glycol dimethyl ether solvent is charged to a reaction vesselunder nitrogen and heated for 10 hours at 100 C. and atmosphericpressure. The reaction product is then discharged, and the compound, bis(cyclopentadicnyl nickel) dimethyl-4,4'-acetylenedibenzoate is recoveredby means of chromatography followed by fractional crystallization.

Example VI A solution comprising 0.1 mole of bis(cyclopentadienylnickel) hexyne-3 and 0.15 mole of dimethyl-octa-2,6-dien- 4-ynoate inbenzene is charged to a reaction vessel under nitrogen and heated for 20hours at C. and atmospheric pressure. The reaction product is thendischarged; solvent is moved by heating in vacuo, and the residue isdissolved in a 30:70 (volume ratio) benzene-petroleum ether mixture andchromatographed on alumina. The eluate is then cooled repeatedly toyield the compound, bis(cyclopentadienyl nickel) dimethyl-octa-2,6 dien4- ynoate by means of fractional crystallization.

Example VII A solution comprising 0.25 mole of bis(cyclopentadienylnickel) pentyne-l and 0.3 mole of bis(m-methoxy phenyl) acetylene indiethyl ether is charged to a reaction vessel which is then pressurizedwith nitrogen. The reaction mixture is heated for 30 hours at 70 C.under a pressure of 80 p.s.i.g. with agitation. The reaction product isthen discharged and the product, bis(cyclopentadienyl nickel)bis(m-methoxyphenyl) acetylene, is obtained by means of chromatographyfollowed by fractional crystallization.

Example VIII A solution comprising 0.1 mole of bis(indenyl nickel)acetylene and 0.2 mole of perfluorobutyne-2 in isooctane solvent ischarged to a reaction vessel which is then pressurized with nitrogen.After heating for 35 hours at 60 C. and a pressure of 50 p.s.i.g., thereaction product is discharged, and excess solvent is strippedtherefrom. The residue is dissolved in a 30:70 (volume ratio)benzenepetroleum ether mixture and chromatographed on alumina. A goodyield of bis(indenyl nickel) perfiuorobutyne-Z is obtained from theeluate by means of fractional crystallization.

My compounds can be used an antiknock agents in a liquid hydrocarbonfuel used in spark ignition internal combustion engines. For this use,Iemploy liquid hydrocarbon fuels of the gasoline boiling rangecontaining from about 0.05 to about 10 grams per gallon of nickel as acompound of my invention. Preferred compositions are hydrocarbon fuelsof the gasoline boiling range containing from about 1.0 to about 6.0grams of nickel per gallon as a compound of my invention.

My compounds may be used as the sole antiknock agent in a liquidhydrocarbon fuel of the gasoline boiling range, or they may be presentin addition to a conventional antiknock agent such as an organoleadcompound. Typical organolead compounds are tetraethyllead,tetramethyllead, dimethyldiethyllead, tetrapropyllead and the like. Thefuels in which my compounds are employed may also contain suchconventional additives as scavengers, antioxidants, and solvents,antiicing agents and the like.

A further use for my compounds is in gas phase metal plating. In thisapplication, the compounds are thermally decomposed in an atmosphere ofa reducing gas such as hydrogen or a neutral atmosphere such as nitrogento form metallic films on a substrate material. These films have a widevariety of applications. They may be used in forming conductive surfacessuch as employed in a printed circuit, in producing a decorative effecton a substrate material, or in applying a corrosion-resistant coating toa substrate material.

The compounds of my invention also find application as additives tolubricating oils and greases to impart improved lubricitycharacteristics thereto. Further, my compounds may be incorporated inpaints, varnish, printing inks, synthetic resins of the drying oil type,oil enamels and the like to impart improved drying characteristics tosuch compositions. Other important uses of my compounds include theiruse as chemical intermediates in the preparation of metal-containingpolymeric materials. Also, my compounds can be employed in themanufacture of medicinals and other therapeutic materials, as well as inagricultural chemicals such as, for example, fungicides, defoliants,growth regulants, and the like.

Another use for my compounds is an additives to residual and distillatefuels, e.g., home heater fuels, jet fuels and diesel fuels, to reducesmoke and soot formation on combustion of the fuel. A still furtherutility for my compounds is as additives to solid propellants to controlthe burning rate.

Having fully defined the novel compounds of my invention, their mode ofpreparation and their many utilities, I desire to be limited only withinthe scope of the appended claims.

I claim:

1. Organometallic compounds having the formula ZC E CZ CyNiNiCy' inwhich Cy and Cy are cyclomatic hydrocarbon groups having to about 13carbon atoms and which are stable toward nickel, and Z and Z areselected from the group consisting of hydrogen, univalent hydrocarbongroups containing up to about 13 carbon atoms, and which are stabletoward nickel, and electron withdrawing groups which are stable towardnickel and are selected from the class consisting of NEC- NEC:C:C

wherein R is a monovalent hydrocarbon group having up to 10 carbon atomswhich is stable toward nickel, and X is a halogen radical, at least oneof Z and Z being an electron withdrawing group.

2. Process for the formation of the compounds of claim 1, said processcomprising reacting a compound having the formula QCECQ' CyNiNiCy' inwhich Cy and Cy are cyclomatic hydrocarbon groups having 5 to about 13carbon atoms, and Q and Q are selected from the group consisting ofhydrogen and univalent hydrocarbon groups containing from one to about10 carbon atoms, with a compound ZCECZ' in which Z and Z are selectedfrom the group consisting of hydrogen and univalent hydrocarbon groupshaving up to about 13 carbon atoms and which are stable toward nickel,and an electron withdrawing group which is stable toward nickel,selected from the class consisting of 0 ll RO-C NEG- acetyleneclicarboxylate in a non-reactive organic solvent.

5. Process for the formation of his(cyclopentadienyl nickel) dimethylacetylene dicarboxylate, said process comprising reactingbis(cyc1opentadienyl nickel) acetylene and dimethyl acetylenedicarboxylate in tetrahydrofuran.

6. The process of claim 2 wherein the solvent is tetrahydrofuran.

7. The process of claim 2 wherein the reaction temperature is within therange from about 0 to about 110 C.

8. Process comprising reaction bis(cyclopentadienyl nickel) acetyleneand dimethylacetylene dicarboxylate in 10 tetrahydrofuran and separatingthe product, bis(cyclopentadienyl nickel) dimethylacetylenedicarboxylate.

9. The process of claim 2 wherein the groups, Q and Q, are hydrogen.

10. Bis(cyclopentadienyl nickel) dimethylacetylene dicarboxylate.

References Cited in the file of this patent Hubel et al., Journal ofInorganic and Nuclear Chemistry, vol. 9, pp. 204-206 (1959).

Tilney-Bassett, J.A.C.S., vol. 81, pp. 4757-8, Sept. 5, 1959.

Dubeck, J.A.C.S., vol. 82, No. 2, p. 502, Jan. 20, 1960.

1. ORGANOMETALLIC COMPOUNDS HAVING THE FORMULA